Under English law "duress" for the purposes of contract law used to be coercion such that the will was overborne. Now it is a pressure to which there is no realistic alternative. Since that derives from a Hong Kong Case ("Pau On") I am sure I would have heard of an Australian case going so much further. I believe New York law applies some special provisions in relation to "contracts of adhesion" (ie ones in which the choice is between signing or not signing, and there is no possibility of questioning or negotiating any terms).

European law restricts terms in consumer contracts that contrary to the duty of good faith create an imbalance between the rights of the consumer and the business (unless individually negotiated), but the list of examples is very wishy-washy.

I personally favour a more stringent test for contracts of adhesion, but English law has a way to go to catch up on this.